Yoke issues are relatively easy to fix, if you're fairly mechanically inclined. If David is still offering his rebuild kit on sale, you can get most parts necessary for $50 from ramcontrols.com.
If the side art is good and the game is working, I would expect an upright to be in the $700-1000 range, depending on your market. It will most likely reach the higher end of the scale if it has an amplifone, lower end if WG (Amplifone might get $100 more than a WG).
But really, a FAIR price is what you want to pay for it. If you get warm fuzzies from the game or it is one of your grails, or if you think there might be some other interested buyers out there or if they're hard to come by in your market, your FAIR price might be higher.